C#•17mo ago

✅ HTTPClient's GetAsync errors and doesn't get caught

In this code

c#
private async Task<CheckResult> TestHTTP()
{
    ...
    // above code creates httpclient as client
    try
    {
(!)     response = await client.GetAsync(expectedURL);
    }
    catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    catch
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    ...
}

c#
private async Task<CheckResult> TestHTTP()
{
    ...
    // above code creates httpclient as client
    try
    {
(!)     response = await client.GetAsync(expectedURL);
    }
    catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    catch
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    ...
}

c#
private async Task<CheckResult> TestHTTP()
{
    ...
    // above code creates httpclient as client
    try
    {
(!)     response = await client.GetAsync(expectedURL);
    }
    catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    catch
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    ...
}

c#
private async Task<CheckResult> TestHTTP()
{
    ...
    // above code creates httpclient as client
    try
    {
(!)     response = await client.GetAsync(expectedURL);
    }
    catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    catch
    {
        client.Dispose();
        handler.Dispose();
        return CheckResult.TimedOut;
    }
    ...
}

client

client

client

client is a

Httpclient

Httpclient

Httpclient

Httpclient which is supposed to timeout after a delay.
To test that, I tried getting it to access a URL that doesn't work.

client.GetAsync(

client.GetAsync(

client.GetAsync(

client.GetAsync(

).Result

).Result

).Result

).Result throws a

TaskCancelledException

TaskCancelledException

TaskCancelledException

TaskCancelledException , which doesn't get caught

Adding:

This function is supposed to be used in multiple threads.
Maybe having the thread error out and shutdown serve as a "catch" block of sorts can work?
However that is not optimal

How fix???:kekw:

wasabi•8/10/24, 4:27 PM

Well, you obviously have to await it, or the code just goes on even though the request isn't done and hasn't errored yet.

wasabi•8/10/24, 4:27 PM

And then you just need to catch it correctly.

wasabi•8/10/24, 4:28 PM

What is 'client'?

Wwasabi Well, you obviously have to await it, or the code just goes on even though the r...

ShevaKaduOP•8/10/24, 4:28 PM

that's what the code deoes

ShevaKaduOP•8/10/24, 4:28 PM

httpclient

wasabi•8/10/24, 4:28 PM

And so why are you disposing it?

ShevaKaduOP•8/10/24, 4:28 PM

the code says that

ShevaKaduOP•8/10/24, 4:29 PM

the use case that I have for them requires me to create mutliple, so to prevent the problems with doing that, I dispose of them

wasabi•8/10/24, 4:29 PM

And where do you create it?

wasabi•8/10/24, 4:29 PM

Because it's not created in this method.

Wwasabi Well, you obviously have to await it, or the code just goes on even though the r...

ShevaKaduOP•8/10/24, 4:29 PM

If I change it to response = await client.GetAsync(expectedURL);
it throws a TaskCancelledException , neither of which get caught.

Wwasabi Because it's not created in this method.

ShevaKaduOP•8/10/24, 4:30 PM

it does, I snipped that part

ShevaKaduOP•8/10/24, 5:02 PM

wah

ShevaKaduOP•8/10/24, 6:17 PM

@Patrick

Patrick•8/10/24, 6:18 PM

you need to await your code properly

ShevaKaduOP•8/10/24, 6:18 PM

how?

Patrick•8/10/24, 6:18 PM

by using

await

await

PPatrick by using `await`

ShevaKaduOP•8/10/24, 6:19 PM

in post:

If I change it to response = await client.GetAsync(expectedURL);
it throws a TaskCancelledException , neither of which get caught.

Patrick•8/10/24, 6:19 PM

i dont care to guess what the code looks like now

Patrick•8/10/24, 6:19 PM

many people tell me they've done many things

Patrick•8/10/24, 6:19 PM

this is user error, so you need to post the actual code that you want help with.

ShevaKaduOP•8/10/24, 6:20 PM

updated the post again

ShevaKaduOP•8/10/24, 6:20 PM

that is the code that I have, I reverted it

ShevaKaduOP•8/10/24, 6:20 PM

and it still doesn't work

Patrick•8/10/24, 6:20 PM

it works, just not the way you want it to

Patrick•8/10/24, 6:21 PM

catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)

catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)

there is a condition here, when the inner exception is of type TimeoutExceptionwhen the inner exception is of type TimeoutException

ShevaKaduOP•8/10/24, 6:21 PM

and then a "catch" without that below

Patrick•8/10/24, 6:21 PM

you're handling both exception branches in the same way as well.

ShevaKaduOP•8/10/24, 6:21 PM

shouldn't it trigger?

Patrick•8/10/24, 6:21 PM

yes, it will "trigger".

PPatrick yes, it will "trigger".

ShevaKaduOP•8/10/24, 6:21 PM

but the app still crashes due to it???

Patrick•8/10/24, 6:22 PM

I don't know what "it" is, if your app is crashing, it's not due to that snippet

ShevaKaduOP•8/10/24, 6:22 PM

it points to that line

Patrick•8/10/24, 6:22 PM

again, I don't know what "it" is

ShevaKaduOP•8/10/24, 6:22 PM

taskcancelledexception - task cancelled due to httpclient reaching timeout

ShevaKaduOP•8/10/24, 6:22 PM

that is what it said

Patrick•8/10/24, 6:22 PM

if you use itit one more time, I'm going to leave this thread

ShevaKaduOP•8/10/24, 6:23 PM

the log

Patrick•8/10/24, 6:23 PM

how does a log point to that line?

ShevaKaduOP•8/10/24, 6:24 PM

I used that code, ran the app in debug (button with filled in green arrow), pressed the button that ran that function, the app crashed, visual studio lights up that line and shows taskcancelledexception

Patrick•8/10/24, 6:24 PM

That's not a log then, is it?

Patrick•8/10/24, 6:24 PM

That's the debugger breaking on an exception. That doesn't mean your app has crashed either.

Patrick•8/10/24, 6:24 PM

It can mean you're breaking on all exceptions, which means you can just press F5/continue

ShevaKaduOP•8/10/24, 6:25 PM

why is it not breaking on other exceptions in try/catch blocks?
okay, let me try

ShevaKaduOP•8/10/24, 6:25 PM

okay, maybe that

Patrick•8/10/24, 6:25 PM

I don't know. You're expecting a stranger to have remote answers to an environment they are not privy to.

Patrick•8/10/24, 6:25 PM

It is a guess.

PPatrick It is a guess.

ShevaKaduOP•8/10/24, 6:30 PM

you're right, that is what happened

ShevaKaduOP•8/10/24, 6:31 PM

it did catch the error, I changedthe settings to break at all exceptions

ShevaKaduOP•8/10/24, 6:31 PM

thanks!